Berkeley Prof say California still has work to do to prepare for the big one

A map depicting California's most earthquake-prone areas.

Courtesy Southern California Earthquake Center

For University of California, Berkeley Professor and former Architecture Department Chair Mary Comerio, 2010 is shaping up to be a busy year. When the magnitude-8.8 earthquake hit Chile on February 27, the architect and disaster-recovery expert was in Haiti on a mission relating to that nation’s January 12 magnitude-7.0 quake. As a consultant to the post-disaster branch of the United Nation’s Environment Program, Comerio was brought in to identify and strategize recovery issues. She also assisted the Earthquake Engineering Research Institute (EERI) in collecting scientific data. Comerio’s research over the past two decades has focused on the costs and benefits of seismic rehabilitation for existing buildings, post-disaster recovery and reconstruction, and loss modeling.

The Architect’s Newspaper:Recent events have us wondering how we would fare if a recent study from the U.S. Geological Survey—that there is a 99.7 percent chance of California having a magnitude-6.7 or larger earthquake during the next 30 years—is borne out. How would you assess our state’s overall preparedness for a major seismic event?

Mary Comerio: California is probably the best-prepared place in the world. With that said, we certainly have things to worry about. We have very good building codes, so many of our modern buildings will do fine. But we still have older concrete buildings that are vulnerable. Particularly, we happen to have a lot that are built in the 1920s, and again in the 1960s, before the building codes really changed. We also have what are known as “soft-story” buildings—the office and residential buildings that have a big open ground for either parking garages or commercial spaces. Those buildings are vulnerable, and we will have damage. It won’t be as dramatic and widespread as something in Haiti, but we will have pockets of very difficult damage. We will have lots of people displaced, depending on the size of the earthquake. We could have higher death rates than we’ve seen depending on the time of day. If either Loma Prieta or Northridge had been a little longer, or, in Northridge’s case, not on holiday at 5:00 a.m., a lot more people might have died.

Are there ways to reconcile the economic realities of earthquake-preparedness with the safety of residents?

Yes, there are. Much of the work that’s being going on with the Pacific Earthquake Engineering Research Center [PEER] at UC Berkeley and other universities has a focus specifically on the lifelines—electrical transmissions, highways and bridges. There’s a great deal of very targeted research on how to improve those important backbones of society, and make them safer. When it comes to buildings, the focus has been on targeting the most vulnerable buildings and work on those as a policy issue.

For example, in San Francisco, probably half the buildings are soft story if you think about all the houses that are over garages. The city of San Francisco has taken an approach to make a mandatory ordinance—this is in process, but it’s going to come, I think, with some bond funding to help finance it—that targets the most vulnerable of that building type. So maybe 12,000-14,000 of the buildings, the very large building or corner buildings where you’re likely to have very high probabilities of collapse, would be required to be retrofitted.

Similarly, we’re doing work at PEER on older concrete buildings, and trying to understand which structural typologies are the most vulnerable, which building types they are and what subset of the inventories are in various cities, so that there is an approach that both local governments and owners find more palatable. We’re not just sweeping through whole categories, but focusing on the most vulnerable.

What do you see as the relationship between green and seismic right now, when there is so much emphasis on retrofitting existing buildings?

There is an important opportunity for working in tandem with the green movement and renovations of existing buildings. Your building isn’t going to be very sustainable if it falls down. If you do this renovation in year one, and in year three it collapses in an earthquake, you haven’t done much for sustainability. Typically, people operate in silos. The architects don’t always talk to the structural engineers; the mechanical engineers kind of live in their own world. The green movement helped bring some of those groups together, and the next step is to start to bring some of the seismic safety components into that.

How can we create a better dialogue between the different disciplines to promote a safer environment and more unified movement?

That’s certainly a goal of an organization like EERI, which is a multi-disciplinary organization. Its members include sociologists, planners, architects, psychologists and geotechnical engineers. But one organization isn’t enough. I think civic groups are actually really important. The San Francisco Planning and Urban Research Association [SPUR] has been incredibly important in bringing together developers, architects, building owners and tenants to talk about the soft-story issue. It really needs to be in the civic realm—because that’s where many of the players are. The owners and the tenants don’t come to our technical meetings.

Should architects take more action regarding seismic legislation?

We haven’t been involved enough. I think we’ve tended to sort of wait at the sidelines, and it is important. On the other hand right now, right now the only issues are jobs and health care. That’s all anybody is talking about legislatively, whether it’s at the state level or the federal level.

Presumably, there will be more seismic-related legislation at some point. What do you see as next in that realm?

I think the next ones will involve performance-based design. We’re not ready to go there yet, but there is a lot of research on this. We’re starting to see changes from absolute prescriptions in the building code to really understanding how buildings perform and designing for those performance levels.

How long do you think it will be before this is introduced into the codes?

Anytime you’ve got new innovative ideas, there’s a timeline of about 20 years before they are really adopted. We’re probably 10 years into the early adopters of different performance-based concepts, and so we’re just starting to see architects and engineers working with these ideas. It’s being experimented with—taking the research and translating it into practical terms that practitioners can use. I think it has another decade before we really start to see changes at the code level, but it’s definitely what’s coming.